In recent years there has been an increasing demand for apparatus for controlling electrical devices such as receptacles and switches from a remote source, such as a computer or a microcontroller as well as for means for determining whether a remote electrical appliance, such as a lamp, is on or off, and providing such information back to the computer or microcontroller. For example, remote control of a switch or receptacle can permit lights to be turned on or off in a programmed sequence. By use of remote control, the power available at a receptacle may be varied so that a lamp plugged into the receptacle may be dimmed from a remote source.
There are many uses for remotely controlled devices in the area of energy conservation. For example, by monitoring exhaust fans in a building to determine which fans are running, a computer can control the fan based upon the time of day or other information so that the fan does not run in an unoccupied building.
Conventionally, remote control of receptacles and switches has been accomplished by the use of radio or infra-red frequencies to pass information to and from electrical devices, such as receptacles or switches. The controlled device is manufactured with electronic components contained within the device. There are limitations to this type of device. Interference from other radio systems may cause devices to switch on or off unpredictably. Interference from neighboring electrical devices may cause unpredictable results. Infra-red requires a "line of sight" to the device and is therefore also limited.
Another system for remote control of electrical devices uses the AC power lines as a carrier and superimposes a controlling signal at a high frequency. This method also has limitations. For example, when lamps are switched on, this system may not be able to switch them off because the temperature change at the lamp may cause interference. Further, there are problems in trying to control fluorescent lamps with this system and discharge lamps or halogen lamps cannot be controlled.
The control systems discussed above all use manufactured modules providing an electrical receptacle into which the controlled device is plugged, the module in most cases plugged into an existing receptacle to receive power. These remotely controlled devices are surface mounted and may be unattractive to look at, expensive, and are provided in limited styles and colors, which may not match the decor of their surroundings.
It is desirable to provide a controlling system that makes use of existing receptacles and switches and which can control such devices while they are mounted within an electrical box in the normal manner with a cover plate flush with the surrounding wall surface. The installation would then appear to be an uncontrolled outlet or switch, but would be a safer installation as the controlled device could be switched off completely to provide child safety.
For many years there have been reliable systems for providing control of electrical devices by use of low voltage wiring and electronic control devices. When wiring is used to provide control there is less likelihood of interference and most if not all of the limitations of other systems discussed above are overcome. However, since electronic control devices operate at lower voltages than electrical devices such as receptacles, consideration must be given to several parts of electrical codes in existence in many countries which require:
1. When wiring from two systems having different voltages are present in an enclosure, these wires should be physically separate. PA0 2. Wiring must be protected against mechanical damage. PA0 3. Adequate space must be provided in a box which contains an electrical device. PA0 4. A semiconductor device should not be relied upon as a disconnecting means. PA0 5. Terminations for wiring of both systems must be accessible.
Disclosed in the prior technical literature are a number of enclosures for electrical and control devices. For example, Tashjian, U.S. Pat. No. 1,437,324 (Nov. 28, 1922) discloses a combined conduit, junction box and outlet box with a removable facepiece. The conduit/box is divided into high and low voltage portion by a permanent divider. No means for connecting a device in one portion with a device in the other portion is provided. Both portions are accessible when the facepiece is removed.
Haering, U.S. Pat. No. 1,829,648 (Oct. 27, 1931) discloses an electric receptacle baffle for dividing an electrical box into high and low voltage portions. No means for connecting a device in one portion with a device in the other portion is provided and both portions are accessible when the cover plate is removed.
Ohmit, U.S. Pat. No. 3,082,290 (Mar. 19, 1963) discloses a moveable floor-to-ceiling electrical installation for interior of a building comprised of a divided vertical conduit and a divided box joined to the conduit. The conduit and box are divided into high and low voltage portions. Again, no means are provided for connecting a device in one portion with a device in the other portion.
Ceglia, U.S. Pat. No. 3,146,298 (Aug. 25, 1964) discloses an electrical distribution system. Electrical boxes and a bus duct are provided with means for routing wiring from the bus duct to the boxes.
Fork, U.S. Pat. No. 3,701,837 (Oct. 31, 1972) discloses a multiple electrical service underfloor access housing. The housing is divided into portions for high and low voltage wiring with no means for interconnection.
Fork, et al., U.S. Pat. No. 4,323,723 (Apr. 6, 1982) discloses a surface mounted outlet unit with separate compartments with no means for interconnection between compartments.
Bantz et al., U.S. Pat. No. 5,257,487 (Nov. 2, 1993) discloses a floor box for in-floor activations in a concrete floor divided into separate compartments by a partition with no means for interconnection between compartments.
Nattel et al., U.S. Pat. No. 5,354,953 (Oct. 11, 1994) discloses a cable holding device for holding a telephone cable beside an electrical outlet box so that a modular telephone jack can be mount to a faceplate shared with an outlet in the electrical box, but the telephone cable and jack do not enter the electrical box. Again, there is no connection between the inside of the electrical box and the outside space in which the telephone jack is located.
Yetter, U.S. Pat. No. 5,486,650 (Jan. 23, 1996) discloses a partition for dividing a device box. Again, no means are provided for connecting a device in one compartment of the box with a device in the other compartment.
Cottone, U.S. Pat. No. 5,574,256 (Nov. 12, 1996) discloses a recessed transformer electrical outlet box with integral telephone line connection. A cover plate having a modular telephone jack is provided to cover the recessed electrical outlet, the idea being to hide a line voltage adaptor module associated with a cordless telephone base station. No means are provided for connecting the high voltage wiring in the inner compartment of the box with a low voltage device in the outer compartment.
Fabian et al., U.S. Pat. No. 5,594,207 (Jan. 14, 1997) discloses a self-locking divider plate for dividing an electrical box into physically isolated compartments. No means are provided for connecting high voltage wiring in one compartment of the box with a low voltage device in the other compartment, other than possibly the openings 17c and 17d. Please consider whether these openings could be used to interface a low voltage control circuit with a high voltage controlled circuit.
Lynn, U.S. Pat. No. 5,598,998 (Feb. 4, 1997) discloses an electrical outlet box mounting bracket. The idea is a variant of the Nattel et al. device discussed above.
There is a need, not satisfied by known combined enclosures for electrical and electronic control devices, for a simple, inexpensive, easy to install enclosure for electrical and electronic control devices that can be flush mounted in a wall and which complies with the requirements of electrical codes.